Plant-based estrogens and genetic variations in their breakdown to be studied.

2002 NOV 7 - (NewsRx.com & NewsRx.net) -- The role of plant-based estrogens in modifying breast cancer risk is the subject of a 5-year research study and intervention to be conducted by nutritional epidemiologists at the University at Buffalo (UB).

The research will be funded by a $569,896 Research Career Development Award from the National Cancer Institute to Susan McCann, PhD, research assistant professor of social and preventive medicine in UB's School of Medicine and Biomedical Sciences.

McCann's research will focus on one class of phytoestrogens - plant compounds with estrogen-like activity - called lignans, which are found in the cell walls of fruits, vegetables, whole grains, berries, seeds and nuts. They are the most abundant source of plant-based estrogens in the typical American diet, and flaxseed contains the highest concentration of lignans.

Plant lignans from flaxseed have been shown to modify urinary excretion of two estrogen metabolites that have been associated with breast cancer risk, McCann said. Moreover, epidemiologic studies suggest that cancer risk is lower among populations with higher intakes of lignans (measured by the amount excreted in the urine), she noted, but no studies to date have assessed the association between breast cancer risk and actual dietary intake of lignans.

There also is evidence that a woman's genetic makeup may affect both the quantity of phytoestrogens used by the body and the way estrogens are metabolized. The metabolic process determines the ratio of weak estrogen metabolites (thought to lower the risk of breast cancer) to strong (thought to increase the risk).

McCann and colleagues will investigate the influence of two specific genes associated with breast cancer risk ...